ADVANCE FOR WEEKEND EDITIONS DEC. 1-2--FILE--Smoke rises from the USS Arizona as the ship sinks in this Dec. 7, 1941 black-and-white file photo from the attack on Pearl Harbor. The attacks of Sept. 11 briefly halted sports. It was not the first time sports has felt the impact of world affairs. Sixty years ago this week, Japanese planes bombed Pearl Harbor, plunging the United States into World War II. (AP Photo/USS Arizona Memorial), Also appeared 12/06/02 Ran on: 07-04-2004
The battleship Arizona sinks in the Pearl Harbor attack, which prompted creation of the CIA. CAT

ADVANCE FOR WEEKEND EDITIONS DEC. 1-2--FILE--Smoke rises from the...

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FILE--Soldiers with the U.S. army's 7th Corps huddle in a bunker in Eastern Saudi Arabia with gas masks and chemical suits just after U.S. planes started bombing Iraq in Jan. 18, 1991. (AP Photo/ Peter Dejong, Pool)

Photo: PETER DEJONG

FILE--Soldiers with the U.S. army's 7th Corps huddle in a bunker in...

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Lt. Jeffrey Goodman, left, and Lance Cpl. Jorge Sanchez, drag a wounded civilian away from his burning vehicle during an advance on Baghdad by the 2nd Tank Battalion Friday, April 4, 2003. The man was injured when he raced into the midst of a battle. (AP Photo, Cheryl Diaz Meyer, Dallas Morning News) CAT MANDATORY CREDIT, FORT WORTH OUT, , NO MAGS, TV OUT, INTERNET OUT

While post-traumatic stress disorder (PTSD) was not officially recognized as a clinical condition until 1980 -- it was called "battle fatigue" or "shell shock" in wars prior to Vietnam -- there have been studies of the symptoms in earlier conflicts.

WORLD WAR II

-- The National Center for Post-Traumatic Stress Disorder estimates that one of every 20 World War II veterans suffered symptoms such as bad dreams, irritability and flashbacks.

-- According to Department of Veterans Affairs' statistics in 2004, 25, 000 World War II veterans were still receiving disability compensation for PTSD-related symptoms.

-- Studies suggested that the most poorly treated prisoners of war had fewer symptoms than front-line soldiers because the prisoners were no longer in a position where they had to kill.

KOREA

-- While there are no major studies readily available, a Korean researcher claimed that as many as 30 percent of U.S. troops who fought in Korea and are still alive today may have symptoms of post-traumatic stress disorder.

VIETNAM

-- 15.2 percent of all male veterans (479,000 out of 3,140,000 who served in Vietnam) and 8.1 percent of women (610 out of 7,200) were diagnosed with post-traumatic stress disorder in a 1986-1988 study by the National Vietnam Veterans Readjustment Survey (NVVRS).

-- Almost half of all male Vietnam veterans suffering from PTSD had been arrested or in jail at least once, 34.2 percent more than once and 11.5 percent had been convicted of a felony, according to the same survey.

-- VA statistics in 2004 showed that 161,000 veterans were still receiving disability compensation for PTSD.

-- A major VA study found that about 31 percent of men and 27 percent of women had suffered from PTSD at some point after their return from Vietnam.

PERSIAN GULF WAR, 1991

-- According to a 1996 study in the Journal of Traumatic Stress, rates of PTSD are generally lower among Gulf War veterans than among military personnel from prior wars, perhaps due to lower levels of exposure to combat.

-- A 1999 study by the Journal of Consulting and Clinical Psychology found that rates of PTSD in Gulf War veterans increased significantly over time, with a rate of 3 percent for men, 8 percent for women immediately upon return from the war, climbing to 7 percent for men and 16 percent for women followed up 18 to 24 months later. Approximately 697,000 service members were deployed to the Persian Gulf.

AFGHANISTAN

-- A recent study showed that 18 percent of 45,880 veterans were diagnosed with psychological disorders, including 183 with PTSD.

IRAQ

-- According to a 2005 VA study of 168,528 Iraqi veterans, 20 percent were diagnosed with psychological disorders, including 1,641 with PTSD.

-- In an earlier VA study this year, almost 12,500 of nearly 245,000 veterans visited VA counseling centers for readjustment problems and symptoms of PTSD.

-- The Marines and Army were nearly four times more likely to report PTSD than Navy or Air Force because of their greater exposure to combat situations.

-- Enlisted men were twice as likely as officers to report PTSD.

-- 8 percent to 10 percent of active-duty women and retired military women who served in Iraq suffer from PTSD.

-- Studies show that U.S. women serving in Iraq suffer from more pronounced and debilitating forms of PTSD than their male counterparts.

-- A Defense Department study of combat troops returning from Iraq found 1 in 6 soldiers and Marines acknowledged symptoms of severe depression and PTSD, and 6 in 10 of these same veterans were unlikely to seek help out of fear their commanders and fellow troops would treat them differently.

-- A 2003 study published in the New England Journal of Medicine said about 1 in 6 soldiers returning from Iraq suffered from PTSD. Interviews with those at risk showed that only 23 percent to 40 percent sought professional help, most typically because they feared it would hurt their military careers.